Mower not getting enough fuel.

[showtime96]

I figured I'd start here since you guys know your stuff. But I have a 2001 toro zmaster 72 inch with a kohler command 26 efi. I've had it for 8 years since I bought the house. But recently it started stalling going downhill. So I got a new fuel filter and plugs. The new filter was clear and I could see it wasn't pumping gas consistently and when I'd go downhill it didn't have enough fuel to keep it running. I checked the fuel pump and tightened up the wires and kind of checked the hoses. After that it ran fine for one mow and now after it warms up a bit it starts not getting enough fuel. Do you guys think its the fuel pump or a vaccum issue?

 

[manwithtools]

Could be the rubber fuel lines, I experienced that on a Kubota diesel after about 8-9 years of use. The hoses would collapse when they got hot. Replaced all the rubber hoses and problem was solved.

 

[Mike Folks]

The Alcohol in today's gas, may make the rubber gas supply hoses swell internally. Replace them and see...

 

[Lightning rod]

ShowTime

how do you know that it is starving for fuel ? Couldn't hurt to replace fuel and vacuum lines after 8 years anyway
Could it be Transmission related ? Does going downhill (how steep) Create a transmission/engine load problem?
Does it have problems going uphill ? how steep

Is it only a problem once it gets hot ?
If you mow downhill after a cold start, does it still exhibit the same symptoms?

just thinking out loud

happy Fathers day

 

[showtime96]

Thank you guys. I've noticed it does it more so when it's hot. The one day I mowed all day without a problem it was a cooler day and no sun. It will start and run fine everytime and I can see the fuel filter so I see its pumping fine. After a while its like it pumps then misses then pumps. That's why I thought either weak fuel pump or a bad line somewhere. I may just replace the lines first if that don't work I'll try a new fuel pump. If that don't work I may try a new mower. I've been wanting one anyways lol. This one was free the guy I bought the house from left it for me and I gave him my 42" rider as he was moving in town and this is about 10 acres about 5 movable.

 

[showtime96]

ShowTime

how do you know that it is starving for fuel ? Couldn't hurt to replace fuel and vacuum lines after 8 years anyway
Could it be Transmission related ? Does going downhill (how steep) Create a transmission/engine load problem?
Does it have problems going uphill ? how steep

Is it only a problem once it gets hot ?
If you mow downhill after a cold start, does it still exhibit the same symptoms?

just thinking out loud

happy Fathers day

It's pretty steep around the pond. I can see the fuel filter. When it's pumping normal there is no interruption in the inflow. When its starts acting up the fuel will pump then pause then pump again. Which is why when I go down hill the fuel in the filter goes back toward the inflow and can't get to the outflow hose and it starts to die. I can push down on the filter to get the fuel to go out and it'll start running again. I have to mow really slow once it starts acting up.

 

[greenskeeper]

electric or mechanical fuel pump? If mechanical, check that the screen on the outside of the fuel pump isn't clogged preventing the pump from moving fuel through crankcase pressure.

 

[showtime96]

electric or mechanical fuel pump? If mechanical, check that the screen on the outside of the fuel pump isn't clogged preventing the pump from moving fuel through crankcase pressure.

Electric fuel pump. It's been replaced once before it has hose clamps instead of the chinch rings like all the other spots.

 

[Copymutt]

Any crazed fuel lines, even minor will cause it to **** air instead of fuel.

 

[charbar]

What about the fuel line off the tank? If it comes out of the top of the tank it would have a hose hanging down in the tank that could be messed up.

Or if the feed line is at the bottom of the tank maybe there is something in the tank thats blocking it sometimes.

Might be something to take a peek at anyway.

 

[greenskeeper]

Electric fuel pump. It's been replaced once before it has hose clamps instead of the chinch rings like all the other spots.

Tank full? where is the in-tank pickup located? Lowest point in the tank or moving around sucking air when on a hill?

 

[Mick56]

Also check the vent in the cap.

 

[showtime96]

What about the fuel line off the tank? If it comes out of the top of the tank it would have a hose hanging down in the tank that could be messed up.

Or if the feed line is at the bottom of the tank maybe there is something in the tank thats blocking it sometimes.

Might be something to take a peek at anyway.

It comes out the bottom. And the time I went trough and messed with all the lines I moved this one enough that a little fuel leaked out if the rubber grommet. Thats the time it started running good again for a bit. But I had also let it cool down.

 

[Lightning rod]

like others have said, it sounds like air is getting into the system
but why more so when on a steep incline?
even though the fuel line comes out of the bottom, could the pickup tube still be uncovered or
tank debris is sloshing around on the incline and clogging the pickup
I guess if air is in the system , the hotter the engine, the bigger the bubble, the bigger the problem

on the other hand , you can tell your wife that the guys on the GJ site were of no help
and you are forced to buy a brand new mower ;-)

good luck

 

[ericm]

Next time it happens loosen the gas cap. If the tank vent is clogged fuel won't flow out of it. It takes a while to build up enough pressure differential to stop fuel flow. If the vent is the problem loosening the cap will make it run correctly. Then you can fix the vent.

 

[My Old Tools]

It could be blocking inside the tank. My Kubota ZTR would starve out. I blew out the line from the tank to where I could here it bubbling inside the tank. Worked fine after that. A lot of tank pickups have screens inside.

 

[like2wheel]

Could be the rubber fuel lines, I experienced that on a Kubota diesel after about 8-9 years of use. The hoses would collapse when they got hot. Replaced all the rubber hoses and problem was solved.

Kubota BX?

Mine just started doing this, & a search on a tractor fourm seemed to suggest rust from the fuel level sender clogging the fuel intake in the tank.
But your solution seems to make more sense for the heat symptom.

 

[manwithtools]

Kubota BX?

Mine just started doing this, & a search on a tractor fourm seemed to suggest rust from the fuel level sender clogging the fuel intake in the tank.
But your solution seems to make more sense for the heat symptom.

No, mine was a F Series mower, but at it's heart a 3 cylinder 22hp Kubota diesel. Essentially an earlier design of a BX operating with the steer wheels in the rear. I did have rusty pick up tube in the tank, but that was not the ultimate cause of my issues. It was frustrating to diagnose, as the hose looked and felt fine on the out side.

 

[manwithtools]

It could be blocking inside the tank. My Kubota ZTR would starve out. I blew out the line from the tank to where I could here it bubbling inside the tank. Worked fine after that. A lot of tank pickups have screens inside.

Yep, known issue with the gas powered Kubota ZTR's. My sons' and two others that I know experienced that in the first year.

 

[jagwinn]

Electric fuel pump. It's been replaced once before it has hose clamps instead of the chinch rings like all the other spots.

ACE Hardware has those clinch bands for 1/4" fuel hose...

 

[kelpaso1]

Yep, known issue with the gas powered Kubota ZTR's. My sons' and two others that I know experienced that in the first year.

No, not a known issue with Kubotas. It's peoples lazy, lack of care when filling their fuel tanks and getting **** in the tank. Of course the pickup screen will clog. Some people have no clue when it comes to engines and fuel systems.

 

[manwithtools]

Got to say, all three of the people I know that had this happen called the dealer (one paid for on site service) and all were told "oh yeah, too many plastic shavings from the factory". In my book that makes it a known issue. Two different dealers BTW. All three less than a year old.

 

[Spareparts]

Check the fuel pressure , the efi systems have a little more fuel pressure than the carbed units
clean the tank and replace the fuel lines, I had to replace the pumps on all 3 of our Toro every 2 to 3 years
of course we mowed over 100 acres every week on the golf course. Them pumps were pricy.

 

[firebirdparts]

My gas tank has quit venting, same symptoms. I am mowing with the cap unscrewed a half a turn now. I was somewhat lucky to figure it out, or at least I felt lucky.

 

[dcg9381]

EFI - that's good. Is the fuel pump high pressure? I assume the fuel filter is before that pump.
I had a similar issue on a Rhino 660 (non-EFI). I thought it was the fuel pump, so I put a new electric pump on. It was still (occasionally) getting air in the lines.
I eventually found a very slight nick at the top of the fuel sump.... It got exposed as fuel level decreased. But drove me crazy until I found it.